The Story : The team goes off-world seeking a weapon against the Ori and ends up in serious trouble. Meanwhile, Landry is faced with having to decide whether or not Vala can be trusted to remain at the SGC.

The Story : While assisting SG-3 on an offworld mission, Teal'c encounters a savage alien creature that is killing the inhabitants. SG-1 investigates and learns that a parasite is to blame. The team suspects that the Ori are responsible, but they are shocked when they find out the real cause.

The Story : Mitchell eagerly awaits the next off-world mission, which will be his 200th trip through the Stargate. However, Martin Lloyd returns and seeks help with his movie script. The Pentagon orders the SG-1 team to assist because the decision makers believe a film about intergalactic wormhole travel will provide a good cover story for the Stargate program.

The Story : Vala finds herself alone in a city with no memory of her identity or past life. Meanwhile, Mitchell and Teal'c question a man named Weaver who may have information about Vala's whereabouts.

The Story : SG-1, Adria, and Ba'al continue their quest to search for Merlin's weapon. They defeat the dragon then SG-1 and Ba'al are transported to another planet without Adria. The team search the new location and find Merlin, but being in stasis for so long has weakened him so Merlin passes all of his knowledge on to Jackson via an Ancient device. Now Jackson must build the weapon before Adria finds them.

The Story : Mitchell, Carter and Teal'c arrive on a planet being threatened by the Ori. They decide that a line needs to be drawn and that the Ori must not be allowed to advance any further. Carter attempts to use the Ancient Merlin's technology to prevent the Ori from taking over the planet.

The Story : The SG-1 team learns of yet another world that has been visited by a Prior of the Ori. However, this Prior hasn't issued any threats. The team waits for the Prior's return, only to be shocked by his identity.